SyntaxError for old-style docstrings with multiple statements

[Claudio Jolowicz]

This module

"""
>>> def f():
...     return 42
...
... f()
42
"""

leads to the following backtrace:

Traceback (most recent call last):
  File "/tmp/xdoctest/venv/bin/xdoctest", line 8, in <module>
    sys.exit(main())
  File "/tmp/xdoctest/venv/lib/python3.9/site-packages/xdoctest/__main__.py", line 160, in main
    run_summary = xdoctest.doctest_module(modname, argv=[command], style=style,
  File "/tmp/xdoctest/venv/lib/python3.9/site-packages/xdoctest/runner.py", line 302, in doctest_module
    run_summary = _run_examples(enabled_examples, verbose, config,
  File "/tmp/xdoctest/venv/lib/python3.9/site-packages/xdoctest/runner.py", line 465, in _run_examples
    summary = example.run(verbose=verbose, on_error=on_error)
  File "/tmp/xdoctest/venv/lib/python3.9/site-packages/xdoctest/doctest_example.py", line 560, in run
    code = compile(
  File "<doctest:example.py::__doc__:0>", line 4
    f()
    ^
SyntaxError: invalid syntax

Stepping into the error, it looks like xdoctest invokes compile in single mode even though multiple statements are present.

This does not happen when only PS1 is used.

[Jon Crall]

Does this work with the original doctest module? I would expect using the PS2 ... to prefix a secondary statement should result in an error. From what I understand it should only be used to denote command continuations. The statement f() is not a continuation of the previous AST block, so it should be formatted as such:

"""
>>> def f():
...     return 42
...
>>> f()
42
"""

Alternatively, you can simply use the new xdoctest prefix rule (Use >>> for everything), and it will work.

"""
>>> def f():
>>>     return 42
>>> f()
42
"""

However, if your example does work with the original doctest module, then we should consider supporting it.

[Claudio Jolowicz]

You're entirely right, and the doctest module has the same behavior here. Thank you for clarifying this!